1. Field of the Invention
The present invention relates to a tool holder, and more particularly, to an adapter-exchangeable type tool holder, which includes an adapter having fastening holes formed therein and a spindle having blocks and bolts detachably mounted to the fastening holes, wherein the blocks are respectively rotatable on hinge pins joined to the spindle, so that the spindle can be easily joined to and separated from the adapter.
2. Background Art
In general, there are various types of tool holders, which are used in a tool turret and has a rotary tool mounted detachably. European Patent Laid-open No. EP 1 358 960 A1 discloses a tool holder, which is mainly used in a tool turret. Referring to FIGS. 19 and 20, the tool holder disclosed in European Patent Laid-open No. EP 1 358 960 A1 (hereinafter, called “960 Patent”) includes a collet chuck receiver 4 that is formed on a spindle 2 and a tension-adjustable nut 10 that is fastened to a collet chuck 6, to which a tool 7 is joined, and is joined with the spindle by an external screw 11.
In order to exchange a tool with a new one, after the tension-adjustable nut 10 is released to some extent to widen a gap of a cut portion of the collet chuck, the tool is removed from the tool holder, and then, a new tool is joined to the tool holder (former case). Alternatively, after the collet chuck 6 and the tension-adjustable nut 10 are all removed from the tool holder, a clamp 23 to which a new tool is joined is fit to the spindle and a screw 30 is fastened to a screw hole 20, so that the collet chuck or the clamp is fixed to the spindle (latter case).
First, the former case is carried out to exchange only the tool which can be joined to the collet chuck, but has a problem in that it takes much time to set tools and working efficiency is remarkably decreased because all tools must be controlled in central point and projecting length whenever the tools are exchanged. Moreover, in the case of the latter case for exchanging the whole adapter, all of the screws (in the drawings, four screw holes 20 are illustrated) are released and tightened up again to fix a new clamp (adapter). However, the latter case also has a problem in that it takes much time to exchange the tool due to a series of the process to release and tighten up the screws one by one.
Furthermore, the latter case has another problem in that the state where the adapter is rejoined after being separated from the tool holder is less in degree of precision than the original state because there is no guarantee that the adapter can be joined to the tool holder as it was when the adapter is rejoined after being separated from the tool holder.
In order to solve the above problems, the 960 Patent discloses a tool holder as illustrated in FIG. 21. That is, the tool holder disclosed in the 960 Patent includes a collet chuck receiver 4 formed in a spindle, a clamp 23 formed on the collet chuck receiver 4, and a screw 30 for fastening the clamp 23 to the spindle.
Such a tool holder may be applied to all kinds of adapters, which use or do not use collet chucks, but does not solve the problems of the conventional tool holders illustrated in FIGS. 19 and 20.
First, the tool holder disclosed in the 960 Patent has a problem in that it cannot keep the assembled state before the clamp is separated from the tool holder when the clamp separated from the tool holder is rejoined to the tool holder using the screw 30. Second, the tool holder has another problem in that it takes much time to release and tighten up all of the screws because the adapter can be exchanged only when four screws are all released and tightened up again. Third, the tool holder has a further problem in that the screws may be lost because the screws are not fixed to the clamp.